1. Field of the Invention
The present invention relates in general to a safety system of a motor vehicle, and more particularly to a warning system which indicates whether an emergency spare tire is in the spare tire container or not, that is to say whether the emergency spare tire is being practically used or not.
2. Description of the Prior Art
For obtaining a larger space in a baggage room and/or reducing the weight of the vehicle, some motor vehicles are equipped with an "emergency spare tire" which is designed to be used only in case of an emergency. The emergency spare tire, sometimes called a space saver tire or temporary tire, is one which is reduced in weight and size as compared with a usual tire and is expanded to the size of the usual tire, upon its practical use, by feeding a pressurized air thereinto.
As is understood from the above, the essential purpose of equipping the emergency spare tire is to temporarily deal with an emergency case. Thus, the durability of such an emergency tire is poor as compared with the usual tire, so that it is not desirable to use the emergency spare tire practically for a long time. However, while using a motor vehicle, it sometimes happens that the driver has forgotten the use of the emergency spare tire after replacing the punctured usual tire by the emergency one, or that a relief driver is left uninformed of the use of the emergency spare tire. This is very dangerous when considering the poor durability of the emergency spare tire.